This project's objective is to obtain a more fundamental understanding of narcolepsy cataplexy in humans from research on dogs having a similar disorder. Research will 1) compare affected and normal dogs on polygraphic measures of total sleep, temporal distributions of sleep, and dissociative aspects in normal sleep patterns; 2) compare affected and normal dogs with respect to sleepiness as defined by sleep latency; 3) describe segmental reflex suppression in the motor inhibition of REM sleep and the motor inhibition of cataplexy; 4) describe the suprasegmental inhibitory role of the medullary inhibitory zone in the elaboration of REM sleep and cataplectic motor inhibitory zone in the elaboration of REM sleep and cataplectic motor inhibition; 5) study the effects on cataplexy of various drugs in order to develop hypotheses concerning underlying biochemical defects; 6) assess genetic parameters of cataplexy in dogs.